Primary treatment for glucose intolerance is strict adherence to a diet that minimizes postprandial glucose response, and in many cases, use of medications (insulin or oral hypoglycemic agents).
Before 1921, starvation was the only recognized treatment of diabetes mellitus (DM). Since the discovery of exogenous insulin, diet has been a major focus of therapy. Recommendations for the distribution of calories from carbohydrate and fat have shifted over the last 75 years. Based on the opinions of the time, the best mix to promote metabolic control are listed in Table 1 below.
TABLE 1History of Recommended Caloric Distribution of Persons with DMYearCarbohydrate (%)Protein (%)Fat (%)192120107019504020401971452035198650-6012-20301994*10-20* ^* based on nutritional assessment ^ <10% saturated fat 
Early recommendations limited dietary carbohydrate, because glycemic control was generally better with this type of regimen. However, over the years researchers found that low-carbohydrate, highfat diets were associated with dyslipidemias and cardiovascular disease. In 1950, the American Diabetes Assodation (ADA) recommended increasing the proportion of calories provided by carbohydrate to lower cardiovascular risk. As the medical community gained a greater understanding of diabetes, dietary recommendations continued to evolve by suggesting increased consumption of carbohydrates.
Part of this evolution stemmed from the discovery that not all carbohydrates produce an equivalent glycemic response. Simple sugars, such as glucose, are rapidly absorbed by a human and produce an immediate spike in the blood glucose levels of a diabetic. More complex carbohydrates, such as starches, do not produce such an immediate spike. Complex carbohydrates are not directly absorbed. They are enzymatically converted to glucose, and other simple sugars, during the process of digestion. Thus, complex carbohydrates produce a blunted glycemic response in diabetics, because they are gradually converted to glucose and absorbed at a reduced rate.
Other complex carbohydrates, such as fibers, are considered indigestible. These indigestible carbohydrates are typically polymeric polysaccharides. They contain glycosidic linkages that human enzymes are incapable of cleaving. Thus, while the polysaccharides produce a sense of fullness in the patient, they are not digested and do not ultimately lead to an absorption of glucose.
Tsuji et al demonstrated what impact an indigestible polysaccharide had no blood glucose levels in a rat model at J. Agric Food Chem 1998, 46,2253. Tsuji found that the oral administration of glucose produced significant rise (about a five fold increase) in blood glucose levels after 30 min. By contrast, the indigestible polysaccharide, Fibersol, produced essentially no change in the animals blood glucose levels after 30 min.
Thus, the phrase “indigestible polysaccharide” is a term of art to food and nutritional scientists. It is used to describe a carbohydrate that a human's digestive enzymes are incapable of converting to glucose, or other simple sugars. A number of indigestible polysacharides have been described in the literature. These include pectins, celluloses, plant gums (e.g. guar gum), hemicellulose, polydextrose, xanthan gum, inulin, plant exudates, algal polysarcharides, modified celluloses, modified staches (e.g. Fibersol 2), etc.
Another indigestible carbohydrate is available from Hayashibara Co., Ltd., of Okayama, Japan and is referred to as pullulan. Hayashibara reports that pullulan is an edible plastic having adhesive properties. It reports that pullulan is safe for use as a food ingredient. It has been used as a texturizer in seasonings, dressings, and meat products. Hayashibara also recommends using pullulan as an edible ink.
Hayashibara has evaluated the digestibility of pullulan. It reports that pullulan is indigestible, like cellulose or pectin. The data in Table 2 was reproduced from a Hayashibara sales aid. It describes the effects of digestive enzymes on pullulan.
TABLE 2The effects of different enzymes on Pullulan as reportedby the manufacturer Hayashibara Co. Ltd.Specimen 1*Specimen 2*Enzymatic SourcepH3 hrs22 hrs3 hrs22 hrsPorcine small intestine6.800.720.0880.51Pancreas5.00.460.901.52—Saliva6.00.482.330.482.5 Porcine liver6.80.72—0.72—*Formation of reducing sugars (in mg) per 20 mg of Pullulan (i.e. breakdown of bonds between the glucose subunits of pullulan). 
Other entities besides Hayshibara have also evaluated the properties of pullulan. The readers attention is directed to U.S. Pat. Nos. 5,116,820 and 4,629,725. Hiji reports that pullulan inhibits the absorption of sucrose. Thus, it can be added to foods designed for diabetics at levels of from 0.25% to 5%, based upon the total weight of the carbohydrate present in the food. Hiji also reports that the co-administration of gymnemic acid enhances the anti-absorptive properties of the pullulan.
Kimoto et al reported the results of an animal safety trial carried out with pullulan. Food and Chemical Toxicology 23, (1997) 323-329. Kimoto also reports that pullulan is an indigestible polysaccharide. On page 324, Kimoto et al reports that minimal glucose was generated by pullulan when exposed to enzymes.
Thus a fair reading of the prior art is that pullulan is reported to be an indigestible potysaccharide. This means that humans will not convert pullulan to glucose and the ingestion of pullulan will not increase serum glucose levels. Thus, while the literature teaches that pullulan may have efficacy as a fiber, it would not motivate one to use pullulan as slowly digested carbohydrate. The prior art teaches that such a use would be futile because humans are incapable of converting pullulan to glucose or other simple sugars.